Diminished response to beta‐bungarotoxin in neonatal rat diaphragm.

Publisher Website
Google Scholar
Abstract
The effects of .beta.-bungarotoxin on acetylcholine [ACh] turnover were studied in noenatal rat diaphragms using a gas chromatographic mass spectrometric assay to measure ACh and choline. Injection of neonatal rats (1-15 days old) with a fixed dose of .beta.-bungarotoxin resulted in a shorter time to death in the older animals. This increased lethal potency of .beta.-bungarotoxin in the older rats was correlated with an enhancement of the stimulatory effect of the toxin on ACh synthesis in diaphragm in vivo and in vitro. The reduced effect of .beta.-bungarotoxin in promoting the accumulation of ACh in new-born rat diaphragms was not due to an enhancement by the toxin of ACh output from these preparations. The stimulatory effect of .beta.-bungarotoxin on ACh synthesis in diaphragm is a function of the age of the rat. .beta.-bungarotoxin may be valuable as a probe of the maturation of presynaptic function in rat skeletal muscle.